The present invention is directed to a pneumatic impact wrench used for loosening and tightening differently sized nuts and bolts. Impact wrenches are commonly used by virtually all assemblers of mechanical devices for fastening many sized nuts and bolts. In order to use the impact wrench, socket tools of varying size are used that will fit particular-sized nuts and bolts. However, since assemblers use the same pneumatic impact wrench to assemble many sized nuts and bolts, and only change the socket tools used, overtorquing or shearing of smaller nuts and bolts is very common. This is a result of choosing a pneumatic impact wrench having sufficient torque to fasten the largest nuts and bolts anticipated in an assembly. Since this torque will also be applied to the smaller nuts and bolts, overtorquing and shearing of the nuts and bolts have been all too common.